Surface heater



Nov. 13, 1962 2 Sheets-Sheet 1 Filed May 8, 1961 FIG Fl e 2 INVENTOR. CHA NCEY T. BROWN 3 0 4 2 2 9 H m H. 2 w l II ll 1. b I III] A n 5 2 J L I l I I I I I I I Ill. 6 FT"! V. m 2\l.. 7 2 3 8 3 2 9- m l I Il l I1 I Ll C. T. BROWN SURFACE HEATER Nov. 13, 1962 2 Sheets-Sheet 2 Filed May 8, 1961 FIG FIG

Unit Stats 3,663,442 Patented Nov. 1a., 1%.:

3,063,442 SURFACE HEATER Chauncey T. Brown, Seattle, Wash, assignor, by mesne assignments, to Martin-Marietta Corporation, Chicago,

., a corporation of Maryland Filed May 8, 1961, Ser. No. 108,388 4 Claims. (Ci. 126-2712) This invention relates to an apparatus for applying heat to the surface of various materials such as wood, concrete, asphalt, tile and the like. More particularly this surface heater device is useful for heating an area of a roadway preparatory to and for the attachment of traffic control markers and the like.

Paint is commonly employed to mark center stripes, parking areas, pedestrian zones, left-turn lanes and other such dividing lines. Paint lines are relatively easy to apply. However, its durability and reflective properties on road surfaces are poor. Repeated restriping is necessary on all road surfaces, the frequency of such restriping depending, of course, on traffic volume and density. It it not uncommon to restripe at three to six month intervals in dense trafiic areas. Paint striping is known to flood out or disappear during heavy rainfall at night, which is the situation in which the need for adequate delineation is greatest.

The art of marking road surfaces has recently turned to the more durable and more easily visible form of raised, three-dimensional type marking devices, or buttons. These devices generally require special preparation of the road surface before they can be secured in place. It is with the problem of preparing and securing the markers in place that this invention is particularly concerned.

Other means for marking employ adhesives to bond continuous plastic strips or individual markers to the road surface. The use of such adhesives is greatly facilitated by first heating the road surface, applying the adhesive thereto, and then placing the marking device in position on the adhesive and allowing the adhesive to set. If the adhesive is of the thermosetting type it is advantageous to be able to continue the heat application to the surrounding area to insure full thermosetting in the shortest possible time. Rapid setting of the adhesive is particularly important when lane markers are being installed on roads which are open to traific. Such installation requires closing the lane temporarily and rapid setting of the adhesive will minimize trafiic delays and congestion.

This invention is particularly useful for the application of marking devices which are bonded to the road surface with adhesives of the thermosetting type. Of course, this device is also useful when employing thermoplastic adhesives and for softening asphalt road surfaces for the application of inset markers.

This surface heater comprises a source of fuel and two or more burners arranged to direct their flames against the road surface. One burner acts as a constant source of heat and additionally serves to ignite a second burner. The second burner acts as a booster heater to increase the heat supply for a predetermined time. The second burner is located suificiently close to flame from the first burner to be ignited thereby. Flame from the second burner impinges on the same area to more rapidly apply heat needed under certain conditions during the application process.

Accordingly it is a primary object of this invention to provide a heater which is specially adapted to secure raised markers to a road surface.

Another object is to provide a heater which is particularly adapted to secure to road surfaces raised markers which are placed with thermosetting adhesive.

A further object is to provide a heater which at a predetermined moment will apply additional or supplementary heat for a designated period of time in order to insure proper setting of the thermosetting adhesive.

A further object is to provide a heater which is small, compact and portable so that it may be easily moved by hand from one position to another.

It is also an object of this invention to provide a heater which will preheat the markers before they are actually applied to the road surface.

Another object is to supply a heater which is simple in design and operation and inexpensive to manufacture and which with other advantages permits one person to operate a number of the heaters simultaneously.

These and other features and advantages of the invention will be understood by consideration of the following description and the attached drawings which exemplify the preferred embodiment.

In the drawings:

FIGURE 1 is an elevational view of the heater showing generally the arrangement of the parts;

FIGURE 2 is a diagrammatic view for the purpose of more clearly illustrating the heater control system and burner heads;

FIGURE 3 is a view partially in section of the dash pot and valve by which fuel is supplied for high level heat;

FIGURE 4 is a partial plan view of the heater housing taken along line 44 of FIGURE 1; and

FIGURE 5 is a di-grammatic view of a cart having a plurality of heaters.

General Structure Referring now to FIGURE 1 and the general structure of the invention it may be seen that the heater, generally designated by reference numeral 10; is preferably cylindrical in shape being approximately seven and onehalf inches in diameter and about thirty inches in height. The cylindrical heater design serves both to support the burners and to shield the area being heated from the wind. Of course, the heater 10 may have other cross-sectional shapes such as a square or rectangle to accommodate itself to the particular area being heated.

The heater 10 comprises the main body or cylinder 12. A shallow cap or lid 9 fits over the upper end of the cylinder 12 to permit the fuel tank to be removed if necessary. Cap 9 is held securely by a tight overlapping relationship between the outer wall surface of the cylinder 12 and the inner surface of the skirt of the cap. The cap is provided with an opening in its top so that valve 2% and its control handle 19 may protrude therethrough. Spaced slightly below the head or lip of cap 9 are two short coaxial, supporting shafts (not numbered) secured to and extending outwardly from diametrically opposed points on the cylinder 12. Bale 23, shaped as a square, inverted U from a narrow strip of heavy gauge sheet metal, has the free ends or tips of its legs bent or doubled back. Thus the doubled-back portion is parallel with the leg itself. Holes or openings are provided through the parallel portions thus permitting the bale 23 to be pivotally received on the short supporting shafts. The bale 23 permits the operator to move the heater about from area to area with a minimum of difliculty.

Cylinder 12 is partitioned near its midpoint by partition wall 11. The wall 11 divides the interior of the cylinder generally into an upper compartment 15 and a lower compartment 17. A bottom partition or wall 7 closes the lower compartment 17. A screen may be substituted for wall 7 if it is desired to have hot gases from the burners pass directly into compartment 17.

Cylinder 12 does not contact any surface on which the heater is brought to bear, but rather is supported above such surface by virtue of the cylindrically shaped base 13. Base 13 is larger in diameter than cylinder 12 and is held in spaced, concentric relation to cylinder 12 by a plurality of brackets 35. It will be noted that said brackets 35 are attached to the very lower end of cylinder 12 around its outer circumference. The brackets are also firmly secured to the upper inner circumference of base 13. As a result cylinder 12 is supported well above the surface being treated. Base 13 is also furnished with a plurality of feet 37 for stabilizing purposes and so that the lower edge or end of base 13 does not rest directly on the surface being treated. a

The heater comprising the general structure just described contains and supports a source of fuel, fuel conduits and valves, burners and other appurtenances.

Burners, Fuel Supply, Conduit and Control System It will be seen, referring now to FIGURES l and 2, that upper compartment -15 of the cylinder 12 accommodates a metal bottle or tank 18 which contains a supply of fuel, preferably gas, connected directly to the upper end of tank 18 is first fuel control valve 20 and extending therefrom valve control handle or knob 19. Conduit 21 passes from first valve 20 over the cap 9 and down the side of cylinder 12 to pressure reducing valve 22. Reducing valve 22 functions to reduce the variations in fuel pressure on the supply side and to present a uniform rate of fuel flow and pressure on the down stream side. Conduit 23 extends downwardly from the reducing valve and then branches into two distinct fuel lines. One line or conduit 25 proceeds to an adjustable needle or second valve 24. Needle valve 24 serves both as a shut-off and flame throttling valve for burner 26 (more fully described hereinafter). Conduit 29 extends downwardly from valve 24 along the lower length of cylinder 12, into the space between said cylinder and base 13 and then turns under the bottom end of said cylinder and connects to first burner 26. First burner 26 is a conventional burner head provided with a single circular row of ports.

The second conduit 27 branching from line 23 leads to third fuel control valve 28. Third valve 28 is of the quick opening type and is normally closed by a biasing spring 33 (shown in FIGURE 3) which for purposes of illustration is shown to be mounted internally of the valve. The spring may be located externally of the valve, however. The spring 33 biases the valve head and its stem upwardly to a shut position. It will be understood that to open the valve 28 it is necessary to depress the stem 32 which protrudes upwardly out of and a slight distance from said valve against the force of spring 33. Thus the head moves away from the seat within said valve. On the intake side of the housing of valve 28 is a vertical, or upstanding, bracket or hinge 53 with a hole therein, the purpose of which will be more fully described, infra. V

Conduit 31 connects the exit side of valve 28 with second burner 30. It will be seen that second burner 30 is not annular in shape as is first burner 26 but is designed to project a more concentrated flame. Both burners are directed to surface area lying directly beneath burner 26.

At this junctureit is deemed advisable to discuss more fully the purpose of the dual burner aspect of this invention which purpose was mentioned only briefly at the beginning of this specification. Burner 26 acts to maintain lower compartment 17 at a relatively warm temperature. Its primary function, however, is to apply heat to the surface area directly beneath and Within the confines of the base 13. The second burner has as its function to apply a high and intense level of heat to the same area for a predetermined period of time measured usually in fractions of a minute. The time period is variable according to valve adjustments. The second burner 30 can be seen to extend from conduit 31 in the form of a small diameter cylindrical shield. Burner 30 extends at an angle into the space between cylinder 12 and base 13 and is directed at the same general area alfected by burner 26. The burner 26 more specifically applies a constant low level heat intensity to the surface area. And because of its proximity and relationship to burner 30, burner 26 also serves to ignite burner 30 when fuel is released from valve 28 via conduit 31.

The level of high intensity heat is periodically applied through valve 28 by the use of a dash pot and lever mechanism best seen in FIGURE 3. Other'devices may be used to control the closing rate of valve 28 but for purposes of illustrating this preferred embodiment the structure of FIGURE 3 will be described.

The dash pot, generally designated by the reference numeral 36, comprises a small cylindrical housing 42 which is slightly in excess of two inches deep and slightly more than two inches in diameter. Size, of course, may vary. A piston 38 is located within the dash pot and connected to piston rod 40. The piston 38 may be seen to be of substantially smaller diameter than the cylinder itself. Piston 38 is provided with a conventional piston cup 39 which is made of a resilient, flexible material such as plastic or synthetic rubber or leather. The piston cup 39 is shaped in the nature of a shallow pan with an upwardly and outwardly sloping wall having knifed edges. As can be seen the piston 38 is sectional so as to receive the fiat bottom of cup 39 between the two sections. The two sections of piston 38 and the cup 39 may be securely fas-. tened together by any one of many known means, none of which is shown. The wall of cup 39 sloping upwardly and outwardly is designed to contact the cylinder wall at the upper edge of said cup wall thus closing the annular space between the cylinder and the piston and preventing in a conventionally known manner the air above the piston from escaping around the piston.

Piston rod 40 depends from piston 38 and through a suitably placed opening in the bottom end wall extends outside the cylindrical housing 42. 1A coil spring 41 is placed around the rod 40 between the piston and the lower end wall to urge the piston upwardly. A small orifice 47 is provided in the bottom end wall to permit air to enter between the bottom of piston 38 and the lower end wall of cylindrical housing 42. The upper end wall of housing 42 is provided with a needle valve assembly, to regulate air flow from the space above piston 38. This valve is comprised of a small cylindrical enclosure 44 rising above the center of the upper end wall of housing 42. The upper end wall itself is provided with a small orifice 43 leading to the inside of enclosure 44. A needle 55 is threaded into the top of enclosure 44 and depends therefrom to extend into the orifice 43. An air escape port 45 is provided in the side wall of valve enclosure 44 to permit air from the space above piston 38 to escape to the atmosphere. The amount of air permitted to escape obviously depends on the adjustment of needle 55.

The lower end of piston rod 40 which protrudes from the dash pot 36 has lever 34 connected thereto. The lower end of the rod 40 has attached thereto a prong or fork or yoke 49 to pivotally receive lever 34. A suitable connection is made with yoke 49 so that lever 34 will pivot about a point approximately at its midpoint. One end of lever 34 is designed so that it may be pushed downwardly by finger pressure. The other end of lever 34 has depending therefrom a short vertical bracket 51 which is provided with a hole. Thus a hinge or pivot connection is made between bracket 53 on valve 28 and bracket 51 by aligning the holes and inserting therein a pin or nut and bolt.

The dash pot 36 and lever 34 are so located that the upper end of valve stem 32 of valve 28 contacts the under side of lever 34 between pivot connections 51-53 and 49. Downward pressure on the free end of lever 34 depresses valve stem 32 to open valve 28. It may be seen that the springs 33 and 41 augment each other in forcing the piston upward.

It may now be understood how the valve 28 may be opened and permitted to supply fuel to burner 30 for a predetermined period of time. The needle 55 of valve enclosure 44 is adjusted to permit air to escape through port 45 at a predetermined rate. When lever 34 is pushed down stem 32 and its head or "alve 28 are depressed to fully open valve 28. At the same time piston 38 is carried to the lower end of dash pot 36. Vacuum in the upper chamber (above the piston) as the piston descends draws air past the cup 39 to form an air cushion above the piston. Pressure from springs 33 in valve 28 and 41 on rod 40 urge the piston upwardly against the air cushion. The air cushion will hold the valve open if the needle 55 in valve enclosure 44 is completely closed in orifice 43. As mentioned above, by controlling the escape of air through port 45 the rate of closing of valve 28 may be regulated.

Several modifications of the burner arrangement are contemplated within the spirit and scope of this invention. The burner 30 might be concentn'c with burner 26 either internally or externally of the diameter of said burner 26. On the other hand it is equally possible to eliminate one burner altogether and utilize a single burner to perform both functions.

Such modification could be easily accomplished by eliminating burner 30 and substituting dash pot 36, lever 34 and valve 28 for valve 24. In such a case it would be necessary to keep valve 28 open to a slight degree to permit the burner 26 to provide a constant low level heat intensity. Maintaining valve 28 open slightly could be accomplished by mounting or threading a stop nut 57 on the lower portion 56 of piston rod 40 as indicated in FIG- URE 3. Thus the high level heat intensity could be supplied in the manner described for a twoaburner heater but nut 57 would hold valve 28 open enough to permit low level heat application. An alternative method to stop nut 57 would be a set screw inserted through the top of dash pot 36 to stop piston 38 at a certain point short of full ascent.

FIGURE 4 shows the use to which lower compartment 17 of cylinder 12 is put. By reference to both FIGURES 1 and 4 it will be appreciated that the wall of cylinder 12 has a large opening provided therein and a door 8 with appropriate hinges and latch secured thereto to cover the opening. Since the road markers are usually round, a dispensing cylinder 6 is welded vertically to the door as at 5. A stock of markers may be dropped into the cylinder when the door is swung open. The stock of markers is retained in dispensing cylinder 6 by an interior semicircular ledge or lip 4 at the bottom of said cylinder. When the door is closed the markers are warmed in the preheating chamber 17 and maintained in such condition until needed. It is obvious that the dispensing cylinder 6 may be of any shape desired and may be made detachable and thus interchangeable with other dispensing cylinders. Dotted lines in FIGURE 4 illustrate the door and dispensing cylinder structure when said door is open. The preheating chamber 17 may be utilized to melt the adhesive by placing a container of adhesive therein. By suitable construction said chamber can preheat the adhesive and the markers simultaneously.

FIGURE 5 illustrates diagrammatically how a plurality of the burners 10 may be operated simultaneously. A cart having a low suspended bed 14 and wheels 16 carries several burners. The bed 14 would be designed to be lowered when the cart is rolled into position and raised when the cart is to be moved.

Operation The burner will be described as employing gas for the purposes of illustrating its operation. First fuel valve 20 is turned on to initiate fuel flow from tank 18. The fuel passes to reducing valve 22 and thence to the branch conduits leading to the second valve 24 and third valve 28. Valve 24 is adjusted to permit the desired fuel flow to burner 26 which is then ignited. Flow through third valve 28 is not allowed until lever 34 is depressed to open valve 28. When gas is admitted to burner 30 through valve 28 it is ignited by flame from burner 26 and the high level heat intensity is applied as desired, the time, again, being selected by adjustment of needle 55 in valve enclosure 44.

The heaters may be operated with various types of fuel, it being only necessary to use suitable burner heads. Portable heaters preferably employ compressed, liquified propane or butane. However, kerosene, diesel oil or gasoline are also acceptable, suitable, and equally useful. Liquid fuels can be supplied to the burners by gravity feed. However, it is preferred to use pressurized fuel to obtain clean, hot flames.

To install adhesive bonded markers on a road surface using the thermosetting adhesives, the heater is operated as described above. The length of time second burner 30 is operated will-depend on the amount of heat desired on the road surface. Generally higher temperatures are desired on concrete roadways than on asphalt surfaces. When second burner 38 shuts off the heater is moved-to the side. An adhesive is applied to the hot portion of the road surface, a marker placed in position and the heater then replaced over the marker. The heat level supplied by the continuously operating first burner 26 will prevent the adhesive from cooling before it is thermoset and will thus insure a rapid and thoroughly cured bond. Normally high level heat intensity is not applied after the marker has been placed.

When the heater is used to install marking devices with a thermoplastic adhesive, it is used to preheat the surface in the manner described above so that the adhesive will liquify and thoroughly wet both surfaces to be joined. The adhesive is applied after preheat and the marker set in place. As the road surface and the adhesive cool a firm bond will be achieved. The utility of the heater in this application resides in its ability to rapidly heat the road surface and maintain the surface in a hot condition until the operator can apply the adhesive and marker thereto.

When the heater is used to install inset markers in asphalt roadways, it is operated in the manner described above. However, the second burner may be operated for a considerably longer period of time to supply the more intense heat needed to permit actual removal of the asphalt-gravel mixture. The flame level of the first burner may be increased by opening the first fuel control valve more and thus supply a higher level of constant heat until the operator can remove the section of roadway.

The heater is very useful for installing markers during inclement weather. Full heat readily dries wet surfaces and maintenance heat keeps the surface dry until the adhesive and the marker are in place.

While a preferred form of the invention has been shown and described, the same is not strictly limited thereby, since certain changes in the exact shape, form and arrangement of the various parts may be resorted to without departing from the spirit or scope of the invention as defined in the appended claims.

What is claimed is:

1. A surface heater, comprising:

(a) an upstanding cylindrical body including a base, said base held in spaced, concentric, external rela-. tionship to said body;

(b) a first burner head mounted in said base and arranged to flame continuously downwardly toward a surface on which said base rests;

(c) a second burner head mounted in said base in spaced relation to said first burner and directed toward the surface area impinged upon by said first burner, said second burner being adapted to be ignited by said first burner;

(d) a source of fuel in said body;

(e) fuel conduit means connecting said source of fuel to said first and second burner heads;

(1) valve means in said fuel conduit means for con '7 trolling the flow of fuel to said second burner head; and

(g) an adjustable control means for opening said valve means to permit fuel flow to said second burner head and for closing said valve means at a predetermined rate of closure.

2. A surface heater, comprising:

(a) an upstanding cylindrical body including a base,

said base held in spaced, concentric, external relationship to said body;

(b) a first burner head mounted in said base and arranged to flame continuously downwardly toward a surface on which said base rests;

(c) a second burner head mounted in said base in spaced relation to said first burner and directed toward the surface area impinged upon by said first burner, said second burner being adapted to be ignited by said first burner;

(d) a source of fuel in said body;

(e) fuel conduit means connecting said source of fuel to said first and second burner heads;

(1) valve mean in said fuel conduit means for controlling the flow of fuel to said second burner head, said valve means being normally biased to a closed position.

(g) means to manually open said second valve means;

and

(It) adjustable control means connected to and adapted to gradually close said valve means at a predetermined rate of closure.

3. A surface heater, comprising:

(a) an upstanding cylindrical body including a base,

said base held in spaced, concentric, external relationship to said body;

(b) first and second burner heads, said base maintaining said burner heads spaced from the surface to be heated, each of said burner heads positioned to direct flames downwardly to impinge essentially the same area of surface, said second burner head positioned to be ignitable by the flame from said first burner head;

(c) a fuel supply means in said body;

(d) conduit means connecting said fuel supply means with said first and second burner heads;

(e) a first fuel control valve in said conduit means between said first burner'head and said fuel supply means;

(f) a second fuel control valve in said conduit means connecting said fuel supply means and said second burner head; 7

(g) means to manually open said second fuel control valve; and

()2) variable biasing means adapted to close said second fuel control valve at a predetermined rate of closure.

4. A surface heater, comprising:

(a) an upstanding cylindrical body including a base,

said base held in spaced, concentric, external relationship to said body;

(b) first and second burner heads, said base maintaining said burner heads spaced from the surface to be heated, each of said burner heads positioned to direct flames downwardly to impinge essentially the same area of surface, said second burner head positioned to be ignitable by the flame from said first burner head;

(0) a fuel supply means in said body;

(d) conduit means connecting said fuel supply means and said first and second burner heads;

(e) a first fuel control valve in said conduit means between said first burner head and said fuel supply means;

(1) a second fuel control valve in said conduit means between said fuel supply means and said second burner head; said second valve means being normally biased to a closed position;

(g) means to manually open said second valve means;

and

(h) adjustable control means connected to and adapted to gradually close said second valve means at a predetermined rate of closure.

References Cited in the file-of this patent UNITED STATES PATENTS 1,150,383 Phelps Aug. 17, 1915 1,970,237 Kramer Aug. 14, 1934 2,754,896 Gerstmayr July 17, 1956 2,833,272 Kennepohl May 6, 1958 

